From f18805ee1c4c37632cc5cfbc369223cb1fdd4641 Mon Sep 17 00:00:00 2001
From: Stefan Behnel <stb@skoobe.de>
Date: Thu, 24 Mar 2016 15:40:12 +0100
Subject: [PATCH] make StringStore.__contains__() return True for the empty
 string (which is also contained in iteration)

---
 spacy/strings.pyx | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/spacy/strings.pyx b/spacy/strings.pyx
index aa1f5c92d..c890cdd22 100644
--- a/spacy/strings.pyx
+++ b/spacy/strings.pyx
@@ -116,7 +116,9 @@ cdef class StringStore:
         else:
             raise TypeError(type(string_or_id))
 
-    def __contains__(self, unicode string):
+    def __contains__(self, unicode string not None):
+        if len(string) == 0:
+            return True
         cdef hash_t key = hash_string(string)
         return self._map.get(key) is not NULL